An accelerator pedal and a brake pedal for perceiving acceleration intention or deceleration intention of a driver are provided in a vehicle. If the driver has the acceleration intention, the driver pushes the accelerator pedal. If the driver has the deceleration intention, the driver takes his or her foot off the accelerator pedal and pushes the brake pedal.
When there are many vehicles in a road, a speed of a host vehicle depends on a speed of a preceding vehicle. If the speed of the preceding vehicle decreases, the driver of the host vehicle primarily takes his or her foot off the accelerator pedal to maintain an inter-vehicle distance between the host vehicle and the preceding vehicle using coasting driving. In addition, when the inter-vehicle distance cannot be maintained, the driver of the host vehicle secondarily pushes the brake pedal.
FIG. 5 illustrates a shift pattern applied to a down-shift according to the related art.
Referring to FIG. 5, if the speed of the preceding vehicle decreases in a state in which the speed of the host vehicle is 100 KPH and a currently engaged shift speed stage is an eighth shift speed stage, the driver of the host vehicle is supposed to push the brake pedal for deceleration without an engine brake effect. The shift speed stage is maintained at the eighth shift speed stage until the speed of the host vehicle becomes 60 KPH. After that, if the speed of the preceding vehicle increases, the driver of the host vehicle pushes the accelerator pedal for acceleration. In this case, if a driving force for acceleration is insufficient, a kick-down 8 to 7 shift is performed, thereby deteriorating acceleration responsiveness.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.